1. Field of the Invention
The present invention relates to an electrophotographic image forming process and image forming apparatus which are capable of preventing offset in a toner and a toner-image-receiving layer of an electrophotographic image-receiving sheet upon releasing of a belt and capable of avoiding deterioration in image quality especially in operation over the long run.
2. Description of the Related Art
Proposals have been made on wax in toner-image-receiving layers of electrophotographic image-receiving sheets and wax in toners for use in image fixing using a belt.
For example, Japanese Patent (JP-B) No. 2872268 proposes an image fixing method using a belt, in which a wax in a polymerized toner has a melting point of 55° C. to 75° C. and an image is fixed at a roller temperature of 140° C. to 200° C.
JP-B No. 2967277 proposes an image fixing method using a belt coated with Teflon (registered trademark), in which a wax in a suspension-polymerized magnetic toner has a melting point of 55° C. to 75° C. and an image is fixed at 140° C. to 200° C.
Japanese Patent Application Laid-Open (JP-A) No. 05-104868 proposes a color image-transfer member having a transparent image-receiving layer comprising a thermoplastic resin and containing a wax with a melting point of 90° C. to 170° C., and a color image forming process for fusing, solidifying, and fixing a color toner image on the color image-transfer member using a belt heating and conveying member.
JP-A No. 11-65156 proposes an optically transparent electrophotographic recording material that can be satisfactorily released from the surface of image fixing means and can produce a satisfactorily fixed toner image by controlling the proportion of a wax component deposited on the surface of a toner-image-receiving layer within a specific range, which toner-image-receiving layer mainly comprises a styrene-acrylic resin and the wax component. This publication also refers to the relationship between the melting point of the wax in the toner-image-receiving layer and the drying temperature of the toner-image-receiving layer and mentions the inhibition of bleed out.
These conventional technologies specify the melting points of a wax in a toner and of a wax in an electrophotographic image-receiving sheet, but fail to describe the relationship between these melting points. They neither disclose nor suggest the relationship between a temperature at which the belt is released and the melting point of wax, the relationship among a drying temperature of a coated layer in an electrophotographic image-receiving sheet, the physical properties of a binder in a toner-image-receiving layer, and the wax melting point, and requirements in the drying temperature of a coated layer in the electrophotographic image-receiving sheet. In other words, they do not make a close study on an entire system including a belt fixing and smoothing device, an electrophotographic image-receiving sheet, and a toner. Demands have been made on further improvements and developments on this point.